Iridescent vehicular trim assemblies and multi-shot injection molding methods for making the same

ABSTRACT

A method of making an iridescent, vehicular trim assembly is provided that includes: molding a polymeric base comprising an exterior surface; and over-molding an element over at least a portion of the exterior surface. The element comprises a polymeric, translucent material and an exterior surface with an integral diffraction grating having a thickness from 250 to 1000 nm and a period from 50 nanometers to 5 microns. Further, the molding can be conducted such that the polymeric base is molded with a tint. The method can also include forming a plated region over the exterior surface of the base. In addition, the method can also include cleaning the plated region with a plasma-etching process before the over-molding.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application that claims priority toand the benefit under 35 U.S.C. § 120 of U.S. patent application Ser.No. 15/298,868 filed on Oct. 20, 2016, issued as U.S. Pat. No.10,239,471 on Mar. 26, 2019, entitled “IRIDESCENT VEHICULAR TRIMASSEMBLIES AND MULTI-SHOT INJECTION MOLDING METHODS FOR MAKING THESAME,” the entire disclosure of which is incorporated by referenceherein.

FIELD OF THE INVENTION

The present invention generally relates to iridescent trim assembliesand other exterior vehicular elements, along with methods of making thesame, particularly automotive grilles with a jewel-like appearance.

BACKGROUND OF THE INVENTION

Car enthusiasts and owners of luxury and high-end vehicles arecontinually demanding new aesthetics that justify, at least in part, thehigh cost of such vehicles. Vehicle grilles and other trim elements canbe designed to reflect the luxury and high-end nature of particularvehicle models. For example, vehicular grilles are often fabricated withinteresting shapes and design aspects, some of which may exhibit achrome-like appearance, particular colors and/or other surface finishes.Conceivably, other ornamental features, such as jewels, incorporatedwithin a grille or other trim element might also be of some interest toa potential buyer of a high-end vehicle.

The direct incorporation of jewels, precious metals and/or gemstonesinto a vehicle grille or trim element might satisfy these needs in somerespects at first glance. These jewels, gemstones and precious metalsmight be encapsulated within a translucent grille for a luxuriousaesthetic. Nevertheless, merely adding jewels, precious metals,gemstones and the like to conventional grilles and other trim elementswill significantly increase the overall component cost, and all but themost cost-insensitive car enthusiasts will likely object to thesignificant added cost of these grilles and trim elements. In addition,the inclusion of jewels, gemstones and/or precious metals into avehicular grille increases the likelihood that these individuallyvaluable features will be removed by thieves as a target of relativeopportunity.

Other approaches to upgrading the aesthetics of exterior vehicularelements have focused on mimicking the look of diamonds and jewelswithin a molded plastic part. For example, it is feasible to makefaceted, plastic trim pieces, in which the facets are visible to theunaided eye, that attempt to approximate the look of actual diamonds andjewels. Unfortunately, the results of such approaches are not promising.Generally, such trim features appear to look like costume jewelry and,arguably, could detract from the overall aesthetic of a luxury vehiclerather than enhance it.

Accordingly, there is a need for exterior vehicular elements, such asgrilles and trim elements (and methods of making them), that exhibit aniridescent or jewel-like appearance without a significant cost increaseassociated with the enhancement. In addition, these iridescent,vehicular trim assemblies should maintain their appearance over avehicle lifetime while being exposed to a typical vehicular environment.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an iridescent,vehicular trim assembly is provided that includes: a polymeric basecomprising an exterior surface; and an over-molded element joined to atleast a portion of the exterior surface. The element comprises apolymeric, translucent material and an exterior surface with an integraldiffraction grating having a thickness from 250 to 1000 nanometers and aperiod from 50 nanometers to 5 microns.

According to another aspect of the present invention, a method of makingan iridescent, vehicular trim assembly is provided that includes:molding a polymeric base comprising an exterior surface; andover-molding an element over at least a portion of the exterior surface.The element comprises a polymeric, translucent material and an exteriorsurface with an integral diffraction grating having a thickness from 250to 1000 nm and a period from 50 nanometers to 5 microns.

A method of making an iridescent, vehicular trim assembly is providedthat includes: molding a polymeric base with a tint; forming a platedregion over an exterior surface of the base; and over-molding an elementover the plated region. The element comprises a polymeric, translucentmaterial and an exterior surface with an integral diffraction gratinghaving a thickness from 250 to 1000 nm and a period from 50 nanometersto 5 microns.

According to another aspect of the present invention, an iridescent,vehicular trim assembly is provided that includes: a polymeric basecomprising an exterior surface; and an over-molded element joined to atleast a portion of the exterior surface. Each of the element and thebase comprises a polymeric material and an exterior surface with anintegral diffraction grating having a thickness from 250 to 1000nanometers and a period from 50 nanometers to 5 microns.

According to a further aspect of the present invention, an iridescent,vehicular trim assembly is provided that includes: a polymeric base; aplated region and a plating over at least a portion of the polymericbase; and an over-molded element joined to the at least a portion of thebase. The element comprises a polymeric, translucent material and anexterior surface with an integral diffraction grating having a thicknessfrom 250 to 1000 nanometers and a period from 50 nanometers to 5microns.

According to an additional aspect of the present invention, aniridescent, vehicular trim assembly is provided that includes: apolymeric base comprising an exterior surface; and an over-moldedelement joined to at least a portion of the exterior surface. Each ofthe element and the base comprises a polymeric material and one of theelement and the base comprises an exterior surface with an integraldiffraction grating having a thickness from 250 to 1000 nanometers and aperiod from 50 nanometers to 5 microns.

These and other aspects, objects and features of the present inventionwill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front perspective view of an iridescent trim assembly in theform of a grille affixed to the front of a vehicle according to anaspect of the disclosure;

FIG. 2A is a cross-sectional, schematic view of a grille assembly, suchas depicted in FIG. 1, through line IIA-IIA according to an aspect ofthe disclosure;

FIG. 2B is a cross-sectional, schematic view of a grille assembly, suchas depicted in FIG. 1, through line IIB-IIB according to an additionalaspect of the disclosure;

FIG. 2C is a cross-sectional, schematic view of a grille assembly, suchas depicted in FIG. 1, through line IIC-IIC according to a furtheraspect of the disclosure;

FIG. 2D is an enlarged cross-sectional schematic view a diffractiongrating incorporated into the grille assemblies depicted in FIGS. 1 and2A-2C;

FIG. 3 is a flow chart schematic of a method of making an iridescentvehicular trim assembly according to another aspect of the disclosure;and

FIG. 4 is a flow chart schematic of a method of making an iridescentvehicular trim assembly according to a further aspect of the disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of description herein, the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” “interior,”“exterior,” “vehicle forward,” “vehicle rearward,” and derivativesthereof shall relate to the invention as oriented in FIG. 1. However,the invention may assume various alternative orientations, except whereexpressly specified to the contrary. Also, the specific devices andassemblies illustrated in the attached drawings and described in thefollowing specification are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificdimensions and other physical characteristics relating to theembodiments disclosed herein are not to be considered as limiting,unless the claims expressly state otherwise.

Described in this disclosure are iridescent trim assemblies, includinggrille assemblies and other iridescent exterior elements, for vehicles(collectively, “iridescent vehicular assemblies”), and methods of makingthese assemblies. The iridescent vehicular assemblies contain one ormore diffraction gratings that are integral with one or morecomponent(s) of the elements (e.g., an over-molded element, a polymericbase, etc.), each of which provides sparkle and iridescence to theassembly. Various microscopic features can be added or adjusted withinthe gratings to achieve varied aesthetic effects. Gratings can also beincorporated into various regions within the iridescent trim assembly toachieve other varied, aesthetic effects. Further, the polymeric base ofthese assemblies can be tinted or plated to produce additional aestheticeffects. As the over-molded element of these assemblies is translucentin certain implementations, the tinting and/or plating of the polymericbase is visible through the over-molded element. As for manufacturingand processing, these iridescent trim assemblies, and other iridescentvehicular assemblies consistent with the concepts of this disclosure,can advantageously be injection molded according to multi-shotapproaches.

Referring to FIG. 1, a front perspective view is provided of iridescentvehicular trim assemblies 100 a, 100 b, 100 c that can each be affixedto the front of a vehicle 1 (e.g., in the form of a grille assembly)according to aspects of the disclosure. As depicted, the trim assemblies100 a, 100 b, 100 c are each characterized by an iridescent orjewel-like appearance under ambient lighting (e.g., from the sun). Oneor more diffraction gratings 20 (see FIGS. 2A-2D) are integral with oneor more components of the trim assemblies 100 a, 100 b, 100 c. Inpreferred aspects, these diffraction gratings 20 provide the iridescentor jewel-like appearance of the trim assemblies 100 a, 100 b, 100 c.

As shown in FIGS. 2A-2C, the iridescent trim assemblies 100 a, 100 b,and 100 c each include a polymeric base 70 a-c, respectively, and anover-molded element 10. The polymeric base 70 a-c employed in these trimassemblies is defined at least by an exterior surface 74. For clarity,interior surfaces of the polymeric base 70 a-c are not shown, but onewith ordinary skill in the field of the disclosure will recognize thatone or more interior surfaces of the polymeric base can be affixed,attached or otherwise joined to a vehicle, such as vehicle 1 (see FIG.1), for purposes of employing one or more of these trim assemblies 100a-c with a given vehicle. As for the over-molded element 10 depicted inFIGS. 2A-2C, it can be defined by one or more exterior surfaces 12 andone or more interior surfaces 14.

With regard to the polymeric base 70 a-c employed in the trim assemblies100 a-c depicted in FIGS. 2A-2C, it may comprise any of a number ofpolymeric materials. For example, these polymeric materials can be athermoset, a thermoplastic or a combination or a mixture of these typesof polymeric materials, e.g., silicones, acrylics and polycarbonates.Preferably, the precursor material(s) employed to fabricate thepolymeric base 70 a-c have a high flow rate and/or a low viscosityduring a molding process such as injection molding. In certain aspects,fillers (not shown), e.g., glass, glass-ceramic and/or ceramic beads,particles, fibers, and whiskers, can be added to a polymeric material,serving as a matrix, to form the polymeric base 70 a-c withoutsignificant detriment to the visual aesthetic of the base 70 a-c. Thesefillers can provide added durability and/or additional aesthetic effectsto the iridescent trim assemblies 100 a-c. According to an embodiment,glass fillers are added in the range of 5 to 15% by volume to enhancethe durability of the base 70 a-c to wear and other environmentaleffects.

In some aspects of the disclosure, the polymeric base 70 a-c depicted inFIGS. 2A-2C is tinted with any of a number of colors, including whiteand black pigments and colorant additives. In such aspects, for example,the tinted polymeric base 70 a-c can be fabricated from an acrylic, apolycarbonate, a nylon, an acrylonitrile styrene acetate (ASA) andcombinations of these materials, all of which are conductive to tintingand other coloration. According to other embodiments, the polymeric base70 a-c can be configured with a plating 80 over the exterior surface 74(see, e.g., FIG. 2A). In such aspects, the polymeric base 70 a-c can befabricated from an acrylonitrile butadiene styrene (ABS), apolycarbonate or a combination of these polymeric materials, all ofwhich can be conducive to a process for directly applying a plating 80to its exterior surface 74.

Referring again to the polymeric base 70 a-c depicted in FIGS. 2A-2C, itcan take on any of a variety of shapes, depending on the nature of theiridescent trim assembly 100 a-c employing the base. For example, thepolymeric base 70 a-c can take on a shape with a large aspect ratio whenemployed in an iridescent trim assembly 100 a-c in the form of avehicular grille. In other aspects of the disclosure, the base 70 a-ccan take on nearly any shape indicative of the application of theiridescent trim assembly 100 a-c, e.g., with one or more curvedsurfaces, one or more planar surfaces, etc. According to an aspect ofthe disclosure, the shape of the polymeric base 70 a-c is limited onlyby shapes and configurations not suitable for manufacturing withinjection molding apparatus and associated methods. In preferredaspects, the polymer base 70 a-c is shaped with one or more planarexterior surfaces 74 conducive to the attachment or joining of apolymeric feature, such as over-molded element 10, by an over-moldingprocess.

Still further, the polymeric base 70 a-c of the iridescent trim assembly100 a-c depicted in FIGS. 2A-2C can consist of a single component in apreferred embodiment. In other aspects, however, the polymeric base 70a-c can be formed from multiple parts, preferably with the parts joined,without significant detriment to the overall properties of the base 70a-c. Manufacturing-related considerations may drive the need or desireto configure the polymeric base 70 a-c as one component or as joinedfrom multiple components.

Now referring to the over-molded element 10 depicted in FIGS. 2A-2C, itmay be joined or otherwise attached to one or more exterior surfaces 74of the polymeric base 70 a-c. Typically, the interior surface 14 of theover-molded element 10 is joined or otherwise attached to the exteriorsurface 74 of the polymeric base 70 a-c. In preferred embodiments, theover-molded element 10 is fabricated from a polymeric, translucentmaterial. According to some implementations of an iridescent trimassembly 100 a-c, the over-molded element 10 is characterized by anoptical transmissivity of 85% or more over the visible spectrum (e.g.,from about 390 nm to about 700 nm). Preferably, the over-molded element10 is characterized by an optical transmissivity of 90% or more, andeven more preferably, 95% or more, over the visible spectrum. Further,the over-molded element 10 can be optically clear with no substantialcoloration. In other embodiments, the over-molded element 10 can betinted or otherwise affixed with one or more filters on its exteriorsurfaces 12 and/or interior surfaces 14 to obtain a desired hue (e.g.,blue, red, green, etc.) or other visual effect.

Referring again to FIGS. 2A-2C, the over-molded element 10 of theiridescent trim assemblies 100 a-c is typically fabricated from apolymeric material. These polymeric materials include thermoplastic andthermosetting polymeric materials, e.g., silicones, acrylics, epoxiesand polycarbonates. Preferably, the precursor material(s) employed tofabricate the over-molded element 10 have a high flow rate and/or a lowviscosity during a molding process such as injection molding. In certainaspects, fillers (not shown), including but not limited to glass beadsand particles, can be added to a polymeric material, serving as amatrix, to form the over-molded element 10 without significant detrimentto the optical properties of the element. These fillers can provideadded durability and/or additional aesthetic effects to the iridescenttrim assembly 100 a-c by virtue of being incorporated into theover-molded element 10. Preferably, glass fillers, particles and otherrelated reinforcements, are added in the range of 1 to 15% by volume,depending on the nature of the filler and the desired effect (e.g.,enhanced durability, added light scattering, etc.).

With further regard to the over-molded element 10 employed in theiridescent trim assembly 100 a-c, the element can take on any of avariety of shapes, depending on the nature of the trim assembly andother design considerations. For example, in some embodiments, one ormore of the exterior and interior surfaces 12, 14 of the over-moldedelement 10 are planar (e.g., faceted), non-planar, curved orcharacterized by other shapes. As also understood by those with ordinaryskill in the field, the exterior and interior surfaces 12, 14 can becharacterized with portions having planar features and portions havingnon-planar features. As depicted in FIGS. 2A-2C in exemplary form, forexample, the over-molded element 10 employed in the iridescent trimassembly 100 a-c in the form of a grille has a non-planar (e.g., curved)exterior surface 12 comprising a diffraction grating 20 and a planarinterior surface 14. The non-planar exterior surface 12 aids in ensuringthat moisture, dirt, and other environmental contaminants are limited inextent of their contact with the over-molded element 10. The planarinterior surface 14 aids in joining, bonding or otherwise attaching theover-molded element 10 to the underlying polymeric base 70 a-c.Nevertheless, other shape factors may be employed for the over-moldedelement 10, as motivated by manufacturability, aesthetics, trim assemblydesign considerations and combinations of these factors.

Again referring to the over-molded element 10 depicted in FIGS. 2A-2C,it can consist of a single component in a preferred embodiment. Forexample, the over-molded element 10 can be formed as a single piece withan integral diffraction grating 20 from an injection molding processemploying a single mold. In other aspects, however, the over-moldedelement 10 can be formed from multiple parts, preferably with the partsjoined, without significant detriment to the overall properties of theelement 10. Manufacturing-related considerations may drive the need ordesire to configure the over-molded element 10 as one component or asjoined from multiple components, and joined or otherwise attached to thepolymeric base 70 a-c.

With regard to the configurations of the iridescent trim assemblies 100a-c employing a plating 80 (see, e.g., FIGS. 2A and 2C) over thepolymeric base 70 a-c, the plating can include one or more materialscapable of being deposited through conventional electro-platingtechnologies. In certain implementations, the plating 80 is applied overall or portions of the exterior surface 74 of the polymeric base 70 a-c.As used herein, the “plating,” such as plating 80, can refer to one ormore continuous or semi-continuous regions of the plating 80 disposed onthe polymeric base 70 a-c. In certain aspects, the plating 80 can befabricated from materials suitable for achieving a bright chrome, satinnickel, satin chrome, satin aluminum, gold, copper, silver, bronze andother finishes. These materials employed in the plating 80 can includeone or more metals, e.g., nickel, chromium, aluminum, gold, silver andothers. Further, other processes besides conventional electro-platingtechniques may be employed to prepare the plating 80, including but notlimited to anodizing and vacuum deposition methods.

In certain implementations of the iridescent trim assemblies 100 a-cemploying a plating 80 (see, e.g., FIGS. 2A and 2C), the exteriorsurface of the plating is subjected to a cleaning treatment prior to theformation and joining of the over-molded element 10 over the polymericbase 70 a-c. More particularly, the plating 80 can be contacted with aplasma arc for a period of time (e.g., 5 to 60 minutes) at an intensitysufficient to modify the surface of the plating 80 to enhance adhesionof the polymeric material employed in the over-molded element 10. Incertain implementations, the plasma arc cleans the surface of theplating 80 by forcibly removing impurities. The plasma arc also etchesthe surface of the plating 80 to a surface roughness indicative ofmaterial removal from about 20 to 500 Angstroms below the surface of theplating 80. Ultimately, the effect of the plasma arc on the plating 80is to roughen its surface at a level not observable to the unaided eye,but at a level sufficient to enhance the bonding and joining of theplating 80 with the over-molded element 10. Accordingly, the intendedappearance of the plating 80 through the over-molded element 10, whichis typically translucent, is not visibly affected by the plasma-cleaningsurface treatment.

Now referring to FIGS. 2A-2C, the iridescent trim assemblies 100 a-c canemploy one or more integral diffraction gratings 20 within theover-molded element 10 and/or within the polymeric base 70 a-c. Forexample, an exterior surface 12 of the over-molded element 10 of theiridescent vehicular trim assembly 100 a, 100 b, 100 c includes one ormore diffraction gratings 20, preferably integral with the over-moldedelement 10. As depicted in exemplary fashion in FIGS. 2A-2C, theiridescent vehicular trim assemblies 100 a, 100 b, 100 c include anover-molded element 10 with a non-planar exterior surface 12 having oneor more integral diffraction gratings 20. Some aspects of the iridescenttrim assemblies 100 a-c include a polymeric base 70 a-c with one or moreintegral diffraction gratings 20. These diffraction gratings 20, forexample, can be fabricated within or in close proximity to the exteriorsurface 74 of the polymeric base 70 a-c (see, e.g., FIG. 2B).Preferably, aspects of the iridescent trim assemblies 100 a-c employingone or more diffraction gratings 20 in the polymeric base 70 a-c do notemploy a plating 80 or otherwise employ a plating 80 in regions of theassembly away from the diffraction grating 20 in the polymeric base 70a-c. Accordingly, those configurations of the iridescent trim assemblies100 a-c employing diffraction gratings 20 in their respective polymericbases 70 a-c do so such that these gratings 20 are visible through theover-molded element 10 without obstruction by any plating 80.

As shown schematically in FIG. 2D in cross-sectional form, thediffraction gratings 20 of the over-molded element 10 and/or polymerbase 70 a-c of iridescent trim assemblies 100 a, 100 b, 100 c are formedat a microscopic level. In an embodiment, the diffraction gratings 20have a thickness 38 that ranges from 250 nm to 1000 nm. The thickness 38of the diffraction gratings 20, for example, should be maintained in therange of 250 to 1000 nm to ensure that the iridescent trim assemblies100 a-c (see FIGS. 2A, 2B and 2C) exhibit a jewel-like appearancethrough light diffraction upon illumination in direct ambient lightingwhile also having a minimal effect on the optical clarity of the trimassemblies under non-direct ambient lighting. Preferably, the thickness38 of the diffraction gratings 20 ranges from about 390 nm to 700 nm. Inother embodiments, the thickness 38 of the diffraction gratings 20ranges from 500 nm to 750 nm.

As also shown schematically in FIG. 2D, the grooves of the diffractiongratings 20 within the over-molded element 10 and/or polymer base 70 a-cof an iridescent trim assembly 100 a, 100 b, 100 c can be configured invarious shapes to diffract incident light and produce an iridescent andjewel-like appearance. As depicted in FIG. 2D in exemplary form, thegratings 20 have a sawtooth or triangular shape. In three dimensions,these gratings 20 can appear with a stepped or sawtooth shape withoutangular features (i.e., in the direction normal to what is depicted inFIG. 2D), pyramidal in shape, or some combination of stepped andpyramidal shapes. Other shapes of the diffraction gratings 20 includehill-shaped features (not shown)—e.g., stepped features with one or morecurved features. The diffraction gratings 20 can also include portionswith a combination of triangular and hill-shaped features. Moregenerally, the shapes of the gratings 20 should be such that aneffective blazing angle θ_(B) of at least 15 degrees is present for oneor more portions of each grating, tooth or groove of the diffractiongratings 20. The blaze angle θ_(B) is the angle between step normal(i.e., the direction normal to each step or tooth of the grating 20) andthe direction normal 40 to the exterior and interior surfaces 12, 14, 74of the over-molded element 10 and/or polymeric base 70 a-c having thegrating 20.

Generally, the blaze angle θ_(B) (see FIG. 2D) is optimized to maximizethe efficiency of the wavelength(s) of the incident light, typicallyambient sunlight, to ensure that maximum optical power is concentratedin one or more diffraction orders while minimizing residual power inother orders (e.g., the zeroth order indicative of the ambient lightitself). An advantage of situating a diffraction grating 20 on planarportions or aspects of the exterior and interior surfaces 12, 14, 74 ofthe over-molded element 10 and/or polymeric base 70 a-c (e.g., as shownin exemplary form in FIG. 2B on a planar portion of the interior surface14 and exterior surface 74) is that a constant blaze angle θ_(B) andperiod 36 will result in consistent reflected and diffracted lightproduced from the diffraction grating. Such consistency can be employedby a designer of the iridescent trim assembly 100 a-c to ensure thatparticular jewel-like effects are observable by individuals at differentlocations and distances from the trim assemblies 100 a-c.

As also shown schematically in FIG. 2D, the diffraction gratings 20 ofthe over-molded element 10 and/or polymer base 70 a-c of an iridescenttrim assembly 100 a, 100 b, 100 c are characterized by one or moreperiods 36 (also known as din the standard nomenclature of diffractiongratings). In most aspects of the trim assemblies 100 a-c (see, e.g.,FIGS. 2A-2C), the period 36 of the diffraction grating 20 is maintainedbetween about 50 nm and about 5 microns. In general, the maximumwavelength that a given diffraction grating 20 can diffract is equal totwice the period 36. Hence, a diffraction grating 20 with a period 36that is maintained between about 50 nm and about 5 microns can diffractlight in an optical range of 100 nm to about 10 microns. In a preferredembodiment, the period 36 of a diffraction grating 20 is maintained fromabout 150 nm to about 400 nm, ensuring that the grating 20 canefficiently diffract light in an optical range of about 300 nm to about800 nm, roughly covering the visible spectrum.

Referring again to FIG. 2D, an integral diffraction grating 20 along aportion of exterior surface 12 of an over-molded element 10 or along anexterior surface 74 of a polymeric base 70 a-c (i.e., as otherwiseadjacent to the interior surface 14 of the over-molded element 10 asdepicted in FIG. 2B) is depicted in exemplary form. Incident light 50(typically ambient sun light) at an incident angle α is directed againsta sawtooth-shaped diffraction grating 20 having a thickness 38, a period36 and a blaze angle θ_(B). More particularly, a portion of the incidentlight 50 (preferably, a small portion) striking the grating 20 at anincident angle α is reflected as reflected light 50 r at the same angleα, and the remaining portion of the incident light 50 is diffracted atparticular wavelengths corresponding to diffracted light 60 _(n), 60_(n+1), etc. at corresponding diffraction angles β_(n), β_(n+1), etc.The reflected light 50 _(r) is indicative of the zeroth order (i.e.,n=0) and the diffracted light 60 _(n), 60 _(n+1), etc. are indicative ofthe nth order diffraction according to standard diffraction gratingterminology, where n is an integer corresponding to particularwavelengths of the reflected or diffracted light.

Integral diffraction gratings 20, such as depicted in an enlarged,schematic format in FIG. 2D, are advantageous within the iridescent trimassemblies 100 a, 100 b, 100 c (see FIGS. 2A-2C), particularly withinthe polymeric base 70 a-c, due to their protected location. Inparticular, these gratings 20 are generally protected from damage,alteration and/or wear due to their location as integral within thepolymeric base 70 a-c underneath the over-molded element 10 (see FIG.2B). Given that incident light 50 must pass through the element 10 toreach the grating 20 within the polymeric base 70 a-c and thatdiffracted light 60 _(n), 60 _(n+1), etc., must also pass through theover-molded element 10 to produce an iridescent effect, the diffractionefficiency of gratings 20 within a polymeric base 70 a-c can be somewhatlower than the diffraction efficiency of diffraction gratings 20 thatare located integrally within the over-molded element 10 due to thelight absorption within the element 10. On the other hand, diffractiongratings 20, as configured within the exterior surface 12 of theover-molded element 10 (see FIGS. 2A and 2C) are more susceptible todamage, alteration and/or wear than diffraction gratings 20 within thepolymeric base 70 a-c. Accordingly, a preferred embodiment of theiridescent trim assemblies 100 a-c includes diffraction gratings 20integral within both of the over-molded element 10 and the polymericbase 70 a-c to balance diffraction efficiency and wear resistance.

Referring back to FIGS. 1 and 2A, one implementation of an iridescenttrim assembly 100 a is depicted in a cross-sectional schematic,exemplified in the form of an iridescent vehicular grille. Moreparticularly, the trim assembly 100 a includes a polymeric base 70 adefined at least in part by an exterior surface 74. In certain aspects,as shown in FIG. 2A, the polymeric base 70 a of the trim assembly 100 acontains a plating 80, which may by disposed over all or portions of theexterior surface 74. The trim assembly 100 a also includes anover-molded element 10 that comprises a polymeric, translucent material.The over-molded element 10 is defined by an exterior surface 12 and aninterior surface 14, and is joined to at least a portion of the exteriorsurface 74 (e.g., at the interior surface 14 as shown in FIG. 2A) of thepolymeric base 70 a. Further, the over-molded element 10 includes one ormore integral diffraction gratings 20 (see also FIG. 2D). In someimplementations, as shown in FIG. 2D, the diffraction grating 20 has athickness 38 from 250 to 1000 nanometers and a period 36 from about 50nanometers to 5 microns.

According to certain aspects of the iridescent trim assembly 100 adepicted in FIGS. 1 and 2A, the over-molded element 10 is fabricatedfrom a silicone, preferably a low-viscosity, high flow material topromote flow during injection molding of one or more integraldiffraction gratings 20. In some embodiments, the plating 80 over theexterior surface 74 of the polymeric base 70 a is cleaned, etched orotherwise subjected to a surface treatment to promote adhesion betweenthe over-molded element 10 and the plating 80. Preferably, the plating80 is subjected to a plasma-treatment to clean and etch the plating 80for this purpose. Further, in some embodiments of the trim assembly 100a, the polymeric base 70 a is fabricated from one or more of anacrylonitrile butadiene styrene (ABS) and a polycarbonate material, asthese materials are conducive, or otherwise can be configured, topromote adhesion of the plating 80.

Referring now to FIGS. 1 and 2B, an implementation of an iridescent trimassembly 100 b is depicted in a cross-sectional schematic, exemplifiedin the form of an iridescent vehicular grille. More particularly, thetrim assembly 100 b includes a polymeric base 70 b defined at least inpart by an exterior surface 74. In certain aspects, as shown in FIG. 2B,the polymeric base 70 b of the trim assembly 100 b can contain one ormore integral diffraction gratings 20, which are disposed within, or inproximity to, the exterior surface 74. The trim assembly 100 b alsoincludes an over-molded element 10 that comprises a polymeric,translucent material. The over-molded element 10 is defined by anexterior surface 12 and an interior surface 14, and is joined to atleast a portion of the exterior surface 74 (e.g., at the interiorsurface 14 as shown in FIG. 2B) of the polymeric base 70 b. Further, theover-molded element 10 includes one or more integral diffractiongratings 20 (see also FIG. 2D). In some implementations, as shown inFIG. 2D, the diffraction grating 20 has a thickness 38 from 250 to 1000nanometers and a period 36 from about 50 nanometers to 5 microns.

According to certain aspects of the iridescent trim assembly 100 bdepicted in FIGS. 1 and 2B, the over-molded element 10 is fabricatedfrom a silicone, preferably a low-viscosity, high flow material topromote flow during injection molding of one or more integraldiffraction gratings 20. Further, in some embodiments of the trimassembly 100 b, the polymeric base 70 b is tinted to exhibit one or morecolors, white, grey and/or black features. As such, the polymeric base70 b can be fabricated from one or more polymeric materials including anacrylic, a polycarbonate, a polypropylene, a nylon, an acrylonitrilestyrene acrylate and combinations of these polymeric materials. Inaddition, certain implementations of the trim assembly 100 b arefabricated such that at least a portion of the exterior surface 74 ofthe polymeric base 70 b is cleaned, etched or otherwise subjected to asurface treatment to promote adhesion between the over-molded element 10and the polymeric base 70 b. Preferably, in these aspects, the portionof the exterior surface 74 is subjected to a plasma-treatment to cleanand etch this surface to promote adhesion of the over-molded element 10.

Referring now to FIGS. 1 and 2C, one implementation of an iridescenttrim assembly 100 c is depicted in a cross-sectional schematic,exemplified in the form of an iridescent vehicular grille. Moreparticularly, the trim assembly 100 c includes a polymeric base 70 cdefined at least in part by an exterior surface 74. In certain aspects,as shown in FIG. 2C, the polymeric base 70 c of the trim assembly 100 ccontains a plating 80, which may by disposed over all or portions of aplated region 90. The plated region 90, as also shown in FIG. 2C, isdisposed over all or a portion of the exterior surface 74 of thepolymeric base 70 c. The trim assembly 100 c also includes anover-molded element 10 that comprises a polymeric, translucent material.The over-molded element 10 is defined by an exterior surface 12 and aninterior surface 14. Further, the over-molded element 10 of the trimassembly 100 c is joined to at least a portion of the polymeric base 70c and, more particularly, to at least a portion of the plating 80 and/orat least a portion of the plated region 90. Further, the over-moldedelement 10 includes one or more integral diffraction gratings 20 (seealso FIG. 2D). In some implementations, as shown in FIG. 2D, thediffraction grating 20 has a thickness 38 from 250 to 1000 nanometersand a period 36 from about 50 nanometers to 5 microns.

According to certain aspects of the iridescent trim assembly 100 cdepicted in FIGS. 1 and 2C, the over-molded element 10 is fabricatedfrom a silicone, preferably a low-viscosity, high flow material topromote flow during injection molding of one or more integraldiffraction gratings 20. In some embodiments, the plating 80 over theplated region 90 is cleaned, etched or otherwise subjected to a surfacetreatment to promote adhesion between the over-molded element 10 and theplating 80. Preferably, the plating 80 is subjected to aplasma-treatment to clean and etch the plating 80 for this purpose.Further, in some embodiments of the trim assembly 100 c, the platedregion 90 of the polymeric base 70 c is fabricated from one or more ofan acrylonitrile butadiene styrene (ABS) and a polycarbonate material,as these materials are conducive, or otherwise can be configured, topromote adhesion of the plating 80 disposed on the plated region 90.Further, in some embodiments of the trim assembly 100 c, the polymericbase 70 c is tinted to exhibit one or more colors, white, grey and/orblack features. As such, the polymeric base 70 c can be fabricated fromone or more polymeric materials including an acrylic, a polycarbonate, apolypropylene, a nylon, an acrylonitrile styrene acrylate andcombinations of these polymeric materials. To the extent that thematerial and/or tinting employed in the polymeric base 70 c is notconducive to plating, the incorporation of a plated region 90 asdisposed over the exterior surface 74 of the polymeric base 70 c,ensures that the plating 80 can effectively adhere to the base (i.e.,via the plated region 90).

According to another aspect of the disclosure, a method 200 a of makingan iridescent trim assembly, e.g., iridescent trim assembly 100 a, 100b, is depicted in a schematic flow chart in FIG. 3. In the method 200 a,a step 210 of molding a polymeric base, e.g., polymeric base 70 a, 70 b,that comprises an exterior surface, e.g., exterior surface 74 (see FIGS.2A-2B). As shown in FIG. 3, an injection molding apparatus 302 with ahopper 304 for holding polymeric precursor material 370 can be employedto injection mold the polymeric base. In particular, the injectionmolding apparatus 302 can be operated at a sufficient temperature tomelt or otherwise promote flow of the precursor material 370 through anorifice 316 a into the mold 310 a. The mold 310 a includes two halves312, 314 a. As the precursor material 370 is driven through the orifice316 a and into a cavity defined by the mold halves 312, 314 a, the mold310 a is cooled. Upon cooling in the cavity, the precursor material 370is formed into the polymeric base, e.g., polymeric base 70 a, 70 b. Atthis point, the mold halves 312, 314 a are separated and the polymericbase is removed.

Referring again to FIG. 3, the method 200 a of making an iridescent trimassembly (e.g., trim assembly 100 a, 100 b) also includes a step 250 ofover-molding an over-molded element, e.g., over-molded element 10 overat least a portion of the exterior surface of the polymeric base formedin step 210. As shown in FIG. 3, the injection molding apparatus 302with a hopper 304 for holding polymeric precursor material 410 can beemployed to injection mold the over-molded element, e.g., over-moldedelement 10. In particular, the injection molding apparatus 302 can beoperated at a sufficient temperature to melt or otherwise promote flowof the precursor material 410 through an orifice 316 b into the mold 310b. The mold 310 b includes two halves 312, 314 b. It should beunderstood that the mold half 314 b contains a diffraction gratingsurface 320 a, for forming one or more diffraction gratings, e.g.,diffraction gratings 20 (see, e.g., FIG. 2D), integrally within theover-molded element 10. As the precursor material 410 is driven throughthe orifice 316 b and into a cavity defined by the mold halves 312, 314b, the mold 310 b is cooled. Upon cooling in the cavity, the precursormaterial 410 is formed into the over-molded element disposed over anexterior surface of the polymer base, e.g., an over-molded element 10disposed over an exterior surface 74 of a polymeric base 70 a, 70 b. Atthis point in step 250, the mold halves 312, 314 b are separated and thetrim assembly containing the over-molded element and the polymeric baseis removed, e.g., an iridescent trim assembly 100 a, 100 b (see, e.g.,FIGS. 1, 2A and 2B).

According to some aspects of the method 200 a for making an iridescenttrim assembly as shown in FIG. 3, an optional step 215 for plating theexterior surface of the polymeric base can be conducted, e.g., to form aplating 80 over an exterior surface 74 of a polymeric base 70 a (seeFIG. 2A). More particularly, step 215 can be conducted after formationof the polymeric base in step 210. More particularly, the step 215 forplating can include the deposition of one or more materials capable ofbeing deposited through conventional electro-plating technologies. Incertain implementations, the step 215 is conducted to plate material,e.g., a plating 80, is over all or portions of the exterior surface ofthe polymeric base. In certain aspects, the plating formed from the step215 can be fabricated from materials suitable for achieving a brightchrome, satin nickel, satin chrome, satin aluminum, gold, copper,silver, bronze and other finishes. These materials employed in the step215 for plating can include one or more metals, e.g., nickel, chromium,aluminum, gold, silver and others. Further, other processes besidesconventional electro-plating techniques may be employed in step 215 forpurposes of preparing and forming the plated material, including but notlimited to anodizing and vacuum deposition processing techniques.

According to another implementation of the method 200 a for making aniridescent trim assembly as shown in FIG. 3, an optional step 220 can beconducted to clean the plated surface created in step 215. Moreparticularly, the optional cleaning step 220 can be conducted prior tothe formation and joining of the over-molded element in step 250. Instep 220, the plating over the polymeric base and/or portions of thepolymeric base itself can be contacted with a plasma arc for a period oftime (e.g., 5 to 60 minutes) at an intensity sufficient to modify thesurface of the plating and/or base to enhance adhesion of the polymericmaterial employed in the over-molded element during the subsequent step250. In certain implementations of the method 200 a, the plasma arccleans the surface of the plating and/or polymeric base by forciblyremoving impurities. The plasma arc also etches the surface of theplating and/or the polymeric base to a surface roughness indicative ofmaterial removal from about 20 to 500 Angstroms below the surface. Inessence, the effect of the plasma arc on the plating and the polymericbase is to roughen its surface at a level not observable to the unaidedeye, but at a level sufficient to enhance the bonding and joining of theover-molded element to the plating and/or polymeric base, as formedduring step 250.

According to another aspect of the disclosure, a method 200 b of makingan iridescent trim assembly, e.g., iridescent trim assembly 100 c, isdepicted in a schematic flow chart in FIG. 4. In the method 200 b, astep 210 of molding a polymeric base, e.g., polymeric base 70 c, thatcomprises an exterior surface, e.g., exterior surface 74 (see FIG. 2C).As shown in FIG. 4, an injection molding apparatus 302 with a hopper 304for holding polymeric precursor material 370 can be employed toinjection mold the polymeric base. In particular, the injection moldingapparatus 302 can be operated at a sufficient temperature to melt orotherwise promote flow of the precursor material 370 through an orifice316 a into the mold 310 a. The mold 310 a includes two halves 312, 314a. As the precursor material 370 is driven through the orifice 316 a andinto a cavity defined by the mold halves 312, 314 a, the mold 310 a iscooled. Upon cooling in the cavity, the precursor material 370 is formedinto the polymeric base, e.g., a polymeric base 70 c employed in aniridescent trim assembly 100 c (see FIG. 2C). At this point, the moldhalves 312, 314 a are separated and the polymeric base is removed.

Referring again to FIG. 4, the method 200 b of making an iridescent trimassembly, e.g., iridescent trim assembly 100 c (see, e.g., FIG. 2C),also includes a step 230 of selectively molding a plated region, e.g.,plated region 90 (see FIG. 2C). In the method 200 b, the step 230 ofselectively molding a plated region is conducted to mold the platedregion over an exterior surface of the polymeric base, e.g., exteriorsurface 74 of the polymeric base 70 c (see FIG. 2C). As shown in FIG. 4,an injection molding apparatus 302 with a hopper 304 for holdingpolymeric precursor material 390 can be employed to injection mold theplated region. In particular, the injection molding apparatus 302 can beoperated at a sufficient temperature to melt or otherwise promote flowof the precursor material 390 through an orifice 316 c into the mold 310c. The mold 310 c includes two halves 312, 314 c. As the precursormaterial 390 is driven through the orifice 316 c and into a cavitydefined by the mold halves 312, 314 c, the mold 310 c is cooled. Uponcooling in the cavity, the precursor material 390 is formed into theplated region over all or a portion of an exterior surface of thepolymeric base, e.g., a polymeric base 70 c employed in an iridescenttrim assembly 100 c (see FIG. 2C). At this point, the mold halves 312,314 c are separated and the polymeric base with the plated region isremoved.

Still referring to FIG. 4, the method 200 b of making an iridescent trimassembly (e.g., trim assembly 100 c as shown in FIGS. 1 and 2C) alsoincludes a step of 250 of over-molding an over-molded element, e.g.,over-molded element 10 over at least portion of the exterior surface ofthe plated region and the polymeric base formed in steps 210 and 230. Asshown in FIG. 4, the injection molding apparatus 302 with a hopper 304for holding polymeric precursor material 410 can be employed toinjection mold the over-molded element, e.g., over-molded element 10. Inparticular, the injection molding apparatus 302 can be operated at asufficient temperature to melt or otherwise promote flow of theprecursor material 410 through an orifice 316 b into the mold 310 b. Themold 310 b includes two halves 312, 314 b. It should be understood thatthe mold half 314 b contains a diffraction grating surface 320 a, forforming one or more diffraction gratings, e.g., diffraction gratings 20(see, e.g., FIG. 2D), integrally within the over-molded element 10. Asthe precursor material 410 is driven through the orifice 316 b and intoa cavity defined by the mold halves 312, 314 b, the mold 310 b iscooled. Upon cooling in the cavity, the precursor material 410 is formedinto the over-molded element disposed over the plated region and thepolymer base, e.g., an over-molded element 10 disposed over a platedregion 90 and the exterior surface 74 of a polymeric base 70 c (see,e.g., FIG. 2C). At this point in step 250, the mold halves 312, 314 bare separated and the trim assembly containing the over-molded elementand the polymeric base is removed, e.g., an iridescent trim assembly 100c (see, e.g., FIGS. 1 and 2C).

According to some aspects of the method 200 b for making an iridescenttrim assembly as shown in FIG. 4, an optional step 235 for plating theexterior surface of the plated region formed in step 230 can beconducted. More particularly, the step 235 can be conducted according tothe same principles outlined in connection with step 215 in the method200 a depicted in FIG. 3. Accordingly, step 235 can be used to form aplating (i.e., a plated material) over the plated region formed in theselective molding step 230 (e.g., a plating 80 as formed over a platedregion 90 as shown in FIG. 2C). Still further, the method 200 b can beconducted with an optional step 240 to clean the plated surface createdin step 235. More particularly, the optional cleaning step 240 can beconducted in a manner consistent with the clean step 220 outlinedearlier in connection with the method 200 a (see FIG. 3), e.g., prior tothe formation and joining of the over-molded element in step 250. Instep 240, the plating, plated region and/or portions of the polymericbase can be contacted with a plasma arc for a period of time (e.g., 5 to60 minutes) at an intensity sufficient to modify the surface of theplating, plated region and/or base to enhance adhesion of the polymericmaterial employed in the over-molded element during the subsequent step250. In certain implementations of the method 200 b, the plasma arccleans the surface of the plating, plated region and/or polymeric baseby forcibly removing impurities. The plasma arc also etches the surfaceof the plating, plated region and/or the polymeric base to a surfaceroughness indicative of material removal from about 20 to 500 Angstromsbelow the surface. In essence, the effect of the plasma arc on theplating, plated region and/or the polymeric base is to roughen itssurface at a level not observable to the unaided eye, but at a levelsufficient to enhance the bonding and joining of the over-molded elementto the plating, plated region and/or polymeric base, as formed duringstep 250.

It is to be understood that variations and modifications can be made onthe aforementioned structure without departing from the concepts of thepresent invention, and further it is to be understood that such conceptsare intended to be covered by the following claims unless these claimsby their language expressly state otherwise.

What is claimed is:
 1. An iridescent, vehicular trim assembly,comprising: a polymeric base comprising an exterior surface; and anover-molded element joined to at least a portion of the exteriorsurface, wherein each of the element and the base comprises a polymericmaterial and an exterior surface with an integral diffraction gratinghaving a thickness from 250 to 1000 nanometers and a period from 50nanometers to 5 microns.
 2. The trim assembly according to claim 1,wherein the polymeric material of the over-molded element is atranslucent silicone.
 3. The trim assembly according to claim 2, whereinthe at least a portion of the exterior surface of the base is a treatedsurface from one or both of a cleaning and an etching.
 4. The trimassembly according to claim 3, wherein the at least a portion of theexterior surface of the base is a plasma-etched surface.
 5. The trimassembly according to claim 4, wherein the polymeric base comprises atleast one of an acrylonitrile butadiene styrene (ABS) and apolycarbonate.
 6. The trim assembly according to claim 1, wherein thepolymeric base is tinted in an as-molded configuration and comprises apolymeric material selected from the group consisting of an acrylic, apolycarbonate, a polypropylene, a nylon, an acrylonitrile styreneacrylate and combinations of these polymeric materials.
 7. The trimassembly according to claim 1, wherein the diffraction grating comprisesa thickness from about 390 nm to about 700 nm and a period from about150 nm to about 400 nm.
 8. An iridescent, vehicular trim assembly,comprising: a polymeric base; a plated region and a plating over atleast a portion of the polymeric base; and an over-molded element joinedto the at least a portion of the base, wherein the element comprises apolymeric, translucent material and an exterior surface with an integraldiffraction grating having a thickness from 250 to 1000 nanometers and aperiod from 50 nanometers to 5 microns.
 9. The trim assembly accordingto claim 8, wherein the over-molded element is joined to one or both ofat least a portion of the plating and at least a portion of the platedregion.
 10. The trim assembly according to claim 8, wherein thepolymeric material of the over-molded element is a silicone.
 11. Thetrim assembly according to claim 10, wherein one or both of the at leasta portion of the plating and the at least a portion of the plated regionis a treated surface from one or both of a cleaning and an etching. 12.The trim assembly according to claim 11, wherein the plated regioncomprises at least one of an acrylonitrile butadiene styrene (ABS) and apolycarbonate.
 13. The trim assembly according to claim 8, wherein thepolymeric base is tinted in an as-molded configuration and comprises apolymeric material selected from the group consisting of an acrylic, apolycarbonate, a polypropylene, a nylon, an acrylonitrile styreneacrylate and combinations of these polymeric materials.
 14. The trimassembly according to claim 8, wherein the diffraction grating comprisesa thickness from about 390 nm to about 700 nm and a period from about150 nm to about 400 nm.
 15. An iridescent, vehicular trim assembly,comprising: a polymeric base comprising an exterior surface; and anover-molded element joined to at least a portion of the exteriorsurface, wherein each of the element and the base comprises a polymericmaterial and one of the element and the base comprises an exteriorsurface with an integral diffraction grating having a thickness from 250to 1000 nanometers and a period from 50 nanometers to 5 microns.
 16. Thetrim assembly according to claim 15, wherein the polymeric material ofthe over-molded element is a translucent silicone.
 17. The trim assemblyaccording to claim 16, wherein the at least a portion of the exteriorsurface of the base is a treated surface from one or both of a cleaningand an etching.
 18. The trim assembly according to claim 17, wherein thepolymeric base comprises at least one of an acrylonitrile butadienestyrene (ABS) and a polycarbonate.
 19. The trim assembly according toclaim 15, wherein the polymeric base is tinted in an as-moldedconfiguration and comprises a polymeric material selected from the groupconsisting of an acrylic, a polycarbonate, a polypropylene, a nylon, anacrylonitrile styrene acrylate and combinations of these polymericmaterials.
 20. The trim assembly according to claim 15, wherein thediffraction grating comprises a thickness from about 390 nm to about 700nm and a period from about 150 nm to about 400 nm.